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Diuretic Pregnancy: D — anti-androgenic effects on male foetus

Spironolactone

Brand names: Aldactone

Adult dose

Dose: HFrEF: 25mg OD. Ascites/oedema: 100–400mg OD
Route: Oral
Frequency: Once daily
Max: 400mg/day
HFrEF (RALES trial): 25mg OD if GFR >30 — add if still symptomatic on ACEi + beta-blocker + furosemide. Ascites: start 100mg OD with furosemide 40mg, titrate. Hyperaldosteronism diagnosis: 400mg/day.

Dose adjustments

Renal

GFR 30–60: use with caution, lower starting dose. GFR <30: avoid (severe hyperkalaemia risk).

Hepatic

Used therapeutically in ascites — adjust to UO response. Monitor U&E closely.

Clinical pearls

  • RALES trial: spironolactone 25mg in HFrEF (NYHA III–IV) reduced all-cause mortality by 30% (NNT = 9 over 2 years) — landmark aldosterone antagonist trial.
  • EMPHASIS-HF: eplerenone (more selective MRA) also reduces mortality in HFrEF, with less gynaecomastia.
  • Gynaecomastia: switch to eplerenone if troublesome — same cardioprotection, no anti-androgenic effect.
  • RALES dose for HF (25mg) causes minimal K+ rise. Ascites doses (100–400mg) cause more electrolyte disturbance — check weekly initially.

Contraindications

  • Hyperkalaemia (K+ >5.0 mmol/L)
  • Addison's disease
  • Anuria
  • Concomitant potassium-sparing diuretic (amiloride, triamterene)
  • Severe renal impairment (GFR <30)

Side effects

  • Hyperkalaemia (most important — monitor K+ regularly)
  • Gynaecomastia and breast pain (anti-androgenic effect — dose-dependent)
  • Menstrual irregularities in women
  • GI disturbance
  • Worsening renal function

Interactions

  • ACE inhibitors / ARBs: significant hyperkalaemia risk — check K+ within 1 week
  • NSAIDs: reduced diuretic effect and hyperkalaemia
  • Digoxin: may increase digoxin levels
  • Potassium supplements: avoid unless K+ clearly low

Monitoring

  • U&E (especially K+ and creatinine) at 1 week
  • 4 weeks
  • 3 months
  • then every 6 months

Reference: NICE NG106 Chronic HF; RALES Trial NEJM 1999; NICE BNF 84. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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